TTK is written in C++ but comes with a variety of bindings
(VTK/C++, Python) and standalone command-line programs. It is modular and easy
to extend.
We have specifically developed it such that you can easily write your own data
analysis tools as TTK modules.
> Check out our developer documentation

TTK is open-source (BSD license). You can use it at your
convenience, for open-source or proprietary projects. You are also welcome to
contribute.> Check out our contribution page